From German patent document DE-OS No. 25 27 502 and the DE-OS No. 28 01 381, a batch washing machine with a twin shell washing drum is known, wherein the inner cylinder is suspended by several chains and is driven rotatingly. The batch washing machine is built as a continuous washing machine, wherein the inner cylinder is subdivided by partitions into several washing compartments, filled with different washing liquids and through which the laundry is passed through, step by step. In order to insure the transport of the laundry, in the inner cylinder spirally configured advancement ribs are provided, which at a corresponding rotating motion of the cylinder move the laundry over the partitions. The inner movable cylinder is surrounded by an outer fixed cylinder or only by a half-shell, a free space being thus created between the two, this space being subdivided into segments, corresponding to the washing compartments, wherein the various washing solutions are kept. The inner cylinder is perforated at least in its lower portion, so that the washing solutions can reach its interior spaces.
Batch washing machines with twin-shell washing drums have the best washing efficiency, however they create problems with the support system of the rotating inner cylinder. The chain has to be passed through the washing liquid, which impairs the lubrication of the chain and leads to a short life span of the chain. German patent document DE-OS No. 25 27 502 atmosphere solve this problem with a special sealing system, which however in practice has proven to have quite unsatisfactory results. Besides, the double function of the chain as a support- and a driving means leads to considerable constructive difficulties. The driven cylinder does not have a perfect rotation and due to displacements of the laundry in its inner space turns erratically. This, together with the various chain elongations in the row of chain drives leads to the danger of the inner and outer cylinder brushing against each other, impairing their operation. German patent document DE-OS No. 28 01 381 tries to solve this problem with a complicated driving technique with dynamic force balancing.